Developing forest harvesting regimes that mimic natural forest dynamics requires knowledge on typical species behaviors and how they respond to environmental conditions. Species regeneration and survival after disturbance depends on a species’ life history traits. Therefore, forest succession determines the extent to which forest communities are able to cope with environmental change. The aim of this review was to i) review the life history dynamics of hemi-boreal tree species in the context of ecological succession, and ii) categorize each of these tree species into one of four successional development groups (gap colonizers, gap competitors, forest colonizers, or forest competitors). To do this we embraced the super-organism approach to plant communities using their life history dynamics and traits. Our review touches on the importance and vulnerability of these four types of successional groups, their absence and presence in the community, and how they can be used as a core component to evaluate if the development of the community is progressing towards the restoration of the climatic climax. Applying a theoretical framework to generate ideas, we suggest that forests should be managed to maintain environmental conditions that support the natural variety and sequence of tree species’ life histories by promoting genetic invariance and to help secure ecosystem resilience for the future. This could be achieved by employing harvesting methods that emulate natural disturbances and regeneration programs that contribute to maintenance of the four successional groups.

Climate change and the associated disturbances have disrupted the relative stability of tree species composition in hemiboreal forests. The natural ecology of forest communities, including species occurrence and composition, forest structure, and food webs, have been affected. Yet, the hemiboreal forest zone of Lithuania is the least studied in the country for climate change risks and possible management adaption techniques. This problem is further complicated by the fact that Lithuania uses a traditional centralised forest management system. Therefore, this work proposes assisted natural regeneration (ANR) of tree species as a more viable means of building hemiboreal forest resilience to cope with future climate change risks. The ANR model implies that forest management is localised in local communities, to provide opportunities for the local people to participate in forest management based on local knowledge, thereby facilitating the transition from cultural diversity to biodiversity. Further, ANR is grounded on an ethical framework—deep ecology—to provide ethical justification for the proposal to transit forest management in Lithuania from the traditional centralised segregated system to a community-driven practice. The work combines the theories of ANR, deep ecology, and hemiboreal forest knowledge systems to provide complementary information that builds on gaps in the existing literature. This study is unique in that no previous work has linked ANR and deep ecology in the context of Lithuania’s forest ecosystems.

We can think of forests as multiscale multispecies networks, constantly evolving toward a climax or potential natural community—the successional process-pattern of natural regeneration that exhibits sensitivity to initial conditions. This is why I look into forest succession in light of the Red Queen hypothesis and focus on the key aspects of ecological self-organisation: dynamical criticality, evolvability and intransitivity. The idea of the review is that forest climax should be associated with habitat dynamics driven by a large continuum of ecologically equivalent time scales, so that the same ecological conclusions could be drawn statistically from any scale. A synthesis of the literature is undertaken in order to (1) present the framework for assessing habitat dynamics and (2) present the types of successional trajectories based on tree regeneration mode in forest gaps. In general, there are four types of successional trajectories within the process-pattern of forest regeneration that exhibits sensitivity to initial conditions: advance reproduction specialists, advance reproduction generalists, early reproduction generalists and early reproduction specialists. A successional trajectory is an expression of a fractal connectivity among certain patterns of natural regeneration in the multiscale multispecies networks of landscape habitats. Theoretically, the organically derived measures of pattern diversity, integrity and complexity, determined by the rates of recruitment, growth and mortality of forest tree species, are the means to test the efficacy of specific interventions to avert the disturbance-related decline in forest regeneration. That is of relevance to the emerging field of biocomplexity research.

In this review, we focus on the importance of the dynamics of hemiboreal trees in the existing forest landscape and habitats for the genetic monitoring of community phenology, in order to obtain characteristic plant cycles as well as their responses to seasonal and climatic changes. The goal of our review is to: (i) determine the regenerative behaviour of hemiboreal tree species, (ii) propose a concept for the genetic monitoring of tree dynamics in the main forest habitat types of Lithuania’s forest landscape based on field observations, e.g., community phenology, and (iii) discuss ways of forest self-regulation, natural regeneration, and reproduction. We have chosen Lithuania as a case study for this review because it is a Northern European country that falls completely within the hemiboreal forest zone, which is often overlooked in terms of climate change effects. Our review highlights the importance of understanding the genetic responses of individual tree species and how they interact in the forest community after disturbance, as well as the need to sustainably monitor them at habitat and landscape scales. To enhance the adaptive potential and associated ecosystem services of forests, we propose the development of landscape-genetic monitoring of the differential dynamic properties of ecosystems.

Spontaneous hybrids between the native elms (genus Ulmus L.) have been observed in the forests of Europe. Gene conservation raises questions regarding the genetic background for the complex morphology and taxonomy of elms. Our objective was to dissect morphological and genetic variation in the natural swamps of Ulmus species groups in Lithuanian forests with the aid of leaf morphology and microsatellite (SSR) markers. We sampled leaves from 189 elms at 26 locations to grasp the phenotypic diversity in variable natural habitats in Lithuanian forests. We assigned the elms into six taxonomic and genetics groups based on 31 leaf morphology parameters and tested the genetic differentiation between these six groups at six nuclear SSR loci by using Bayesian and genetic distance-based clustering. The genetic and leaf morphometric analyses of putative elm hybrid swamps indicated a low genetic exchange between U. laevis Pall. and the other Ulmus groups. The genetic and morphometric data supported the differentiation of U. glabra Huds. and U. glabra (female) × U. minor Mill. (male) spontaneous hybrids. In addition, the results of the genetic analysis also confirmed the high level of genome sharing among U. minor and U. minor subsp. minor Richens., where leaf morphology failed to differentiate genetically discrete groups. For gene conservation, we would suggest considering separate gene conservation units selected based on leaf and stem morphology for U. laevis, U. glabra, U. glabra × minor, and the U. minor species complex.